Whether start-up operation is standardized or not plays a decisive role. It not only affects lifespan of machine itself but also production safety of the entire workshop, yield rate of final products.
If start-up process is haphazard and not performed according to established procedures, at best mold will be damaged and raw materials will be scorched by high temperature. In more serious cases, it can easily lead to serious safety accidents such as machine-related injuries or even workshop fires.

 

Therefore, I have compiled this start-up operation guide specifically to help operators on the front lines gradually develop standardized and efficient daily start-up habits.

Before pressing power switch, do not rush to start machine. Thoroughly inspect area around machine, inside and out, to ensure that there are no hidden dangers and that machine is in a normal, ready-to-operate state before proceeding to next step.
1. Environmental and Safety Inspection
Carefully clean area around machine, under moving platen, and inside safety door tracks. Check for any carelessly piled tools, discarded rags, or leftover scraps. Clean up any such debris immediately.
Test front and rear safety doors by pushing and pulling them back and forth several times to ensure smooth sliding.
Also, specifically test function of safety limit switches. Principle is that machine must not perform mold-closing action if safety door is open. This must be repeatedly confirmed; there can be no error.
In addition, check status of emergency stop button on control panel and side of machine. Ensure button pops up normally. Press it a couple of times to test its sensitivity; there should be no button jamming.
2. Lubrication and Hydraulic Circuit Inspection
First, observe hydraulic oil level gauge. Under normal circumstances, oil level should be maintained between one-third and two-thirds full. As long as it falls within this range, there is no problem.
While you're at it, visually inspect hydraulic oil. If oil appears cloudy or black, has a strong, pungent odor, or shows signs of emulsification, do not force machine to start. Starting it abruptly will likely cause various equipment problems.
Also, check oil reservoir of centralized lubrication pump to ensure it has sufficient grease. Critical components like guide rails and crankshafts must be adequately lubricated. Prolonged dry friction operation will quickly damage equipment.
3. Cooling System Inspection
Open all inlet and outlet valves for mold cooling water and oil cooler beforehand.
Observe whether cooling tower is operating normally and whether water pressure remains stable. Check all pipe connections one by one; there must be no leaks or seepage.

1. Basic Power-On Steps
Remember operating sequence: First, close main power switch, then turn on equipment's control system power. Watch control panel patiently and wait for system to complete its self-check process. Only when page displays no error messages or fault codes is power-on process officially complete.
An additional reminder: If injection molding machine has been idle for more than 48 hours, do not rush to start motor after powering on. Let it sit for about 15 minutes to allow internal electrical components to slowly preheat and expel accumulated moisture. This will reduce many subsequent minor malfunctions.
2. Retrieving Process Parameters
In machine's control system, retrieve mold-specific process parameters corresponding to current batch of products.
Use paper process record card to carefully check each item. Core values such as pressure, running speed, molding time, and barrel temperature must be completely consistent. Do not arbitrarily change these parameters; any misallocation will almost certainly result in defective products.

Frankly, heating process is the most easily overlooked step in the entire startup procedure, but its importance is extremely high and it absolutely cannot be taken lightly.
Common plastic raw materials on the market, such as PP, ABS, PC, and PA66, each have different suitable processing temperatures. Parameters must be set strictly according to actual characteristics of material itself; arbitrarily adjusting them based on experience is not advisable.
Cooling water at feed inlet must be continuously circulated throughout process. If cooling water stops working, raw material will soften prematurely and accumulate inside hopper, easily causing bridging and material jamming, which will be extremely troublesome to clean up later.
Once temperature gradually rises to set standard value, remember not to rush into production. Sufficient time must be allowed for constant temperature immersion.
Generally, for small injection molding machines, 15 to 20 minutes of constant temperature immersion is sufficient. For large production equipment, constant temperature time should ideally be maintained at 30 minutes or more. It's better to wait a little longer than to rush into production.
Many people wonder why soaking time is so long. Reason is simple: temperature probe can only collect temperature data from outer wall of barrel; temperature deep inside screw is far from required level. Forcing equipment to start under these conditions can easily bend and damage screw, making it a losing proposition.
In addition, nozzle installation position must be frequently checked to ensure precise alignment with mold positioning ring. Heating coil on outer side of barrel must also be securely attached. Improper attachment leading to uneven heating will cause these components to fail due to high temperatures in a short time.

 

After starting oil pump motor, pay close attention to operating sound of equipment. If you hear any sharp abnormal noises or cavitation noises, stop machine immediately and troubleshoot problem.
Also, observe standby pressure value displayed on system. Maintaining it within normal range is acceptable; excessively high or low pressure indicates an abnormal state.
Before switching to fully automatic production mode, one step is absolutely essential: run all mechanical actions of equipment under no-load in manual control mode.
Repeatedly operate mold opening and closing mechanism several times, observing for smooth operation and any unexplained shaking or vibration. Auxiliary structures such as ejector pins and core pullers should also be tested individually to ensure precise forward and backward positioning, prevent misalignment.
Injection unit's forward and backward movement should also be adjusted slowly at low speed to ensure the nozzle and mold are perfectly aligned, without any deviation or misalignment.

As everyone knows, mold procurement costs are consistently high, and low-pressure protection function is last line of defense against mold damage. This adjustment step must not be skipped under any circumstances.
Adjustment method is not difficult to understand. Simply put, place a thin piece of paper in the middle of mold's closing mechanism. When mold encounters even this slight resistance, machine should immediately stop operating and automatically trigger an alarm.
Remember, absolutely do not skip low-pressure protection test and directly start full-speed mold closing. Any operational error will render the entire mold unusable, resulting in economic losses that no one can afford.
If workshop is equipped with a mold temperature controller, remember to turn it on in advance to preheat mold cavity to required process temperature. Otherwise, high-temperature molten material coming into contact with low-temperature mold will cause a large amount of internal stress to accumulate inside product, leading to cracking and deformation as a common occurrence.

Before officially feeding material into hopper for production, if there is any old material left over from previous batch inside the barrel, it must be thoroughly cleaned.
You can use PE material or a special cleaning agent to repeatedly flush material until molten plastic injected from nozzle is clean and clear, without any impurities or bubbles. Only then can you officially begin feeding material for production.
During first trial production, do not immediately increase injection volume to maximum. Adjust it to about 80% of required amount for finished product, and gradually adjust holding pressure parameters upwards to find the most suitable process data.
Setting parameters too aggressively from outset can easily lead to problems like mold overflow and material spillage, resulting in time-consuming and labor-intensive cleanup.

When cleaning residual adhesive on nozzle surface, all necessary protective equipment, including heat-resistant gloves and professional goggles, must be worn. High temperature of molten adhesive can easily cause severe burns.
For heat-sensitive materials like PVC and POM, which are prone to thermal decomposition, immediately shut off heating function if you smell a pungent odor. Quickly clean and cool material to prevent release of harmful gases that could endanger personal safety.
When equipment is running, there is one absolute rule: never put your hands into mold closing area or ejector pin working area.
In case of material sticking to mold and becoming difficult to remove, always turn off motor power first, open safety door, and take protective measures before proceeding with any cleaning.
Do not place water cups, bottles, or other items containing moisture on top of electrical control cabinet to prevent water leakage and short circuits. Do not pile up flammable materials such as discarded rags or solvents around barrel to avoid ignition of flammable materials in high temperatures, which could cause a fire.

Most motor starting failures are caused by emergency stop switch not resetting or equipment oil temperature being too low. Simply check switch status and patiently wait for oil temperature to preheat to required level; this should generally solve problem.
If screw cannot rotate normally, it is usually due to either insufficient constant temperature soaking time or a faulty transmission coupling. Depending on actual situation, either extend constant temperature time or stop machine and check transmission structure.
Oil leaks in equipment's oil circuit are generally caused by loose pipe joints or aging and failure of sealing rings. Do not operate machine with a faulty system; stopping machine and reporting it for repair immediately is the best course of action.
If machine emits smoke or a burnt smell during operation, it's highly likely that heating coil has burned out or raw material has overheated and decomposed. Immediately shut off all heating functions, manually clean material, and carefully troubleshoot source of problem.

 

In general, starting up an injection molding machine is far more complex than simply connecting power.
It involves coordination of many professional knowledge areas, including hydraulic transmission, mechanical structure, and thermodynamic principles. It's a complete process that requires meticulous attention to detail.
Experienced operators who have worked on-site for years understand that often, taking things a little slower can actually lead to higher overall efficiency.
Spending an extra ten minutes or so carefully performing all checks and preheating procedures before starting machine can prevent a series of subsequent problems such as equipment downtime, machine repairs, and mold damage.
This operating guide can serve as a valuable reference for daily operations in workshop. Whether you're a new employee or an experienced operator, it's beneficial to review and familiarize yourself with it.
Crucial matter of safe production is always hidden in every meticulous detail of starting up machine.